Pin type fastening devices



Jan. 21, 1964 s. BARNETT 3,118,206

PIN TYPE FASTENING DEVICES Filed May 11, 1962 United States Patent E is 3,118,265 PIN TYRE FASTENING DEVIEES Earnett, 91 Reehov nd Aleph, Safad, Israel Filed May 11, 1962, Ser. No. 193,958 (Ilairns priority, applieation Ireland May 15, 1961 1 Ciairn. (Cl. 24157) This invention relates to pin-type fastening devices of the safety pin kind and in particular to the kind such as those used on brooches, badges and similar articles.

It is an object of the invention to provide an improved form of such fastening device that will be easy to open and close when desired, but will be unlikely to be released unintentionally.

For convenience of description it will be assumed herein that the fastening device is orientated so that the pin moves down in a vertical plane towards a horizontal closed position, in which it is received and retained by a catch, although it will be obvious that in use the device may occupy any position. Moreover the end of the catch nearer to the pin axis will be referred to as its forward end.

According to the present invention, a pin-type fastening device includes a catch for retaining the end of the pin, comprising a rocker of generally tubular form mounted in a base to pivot about an axis substantially perpendicular to the tube axis and to the plane in which the pin moves and arranged so that as the pin is closed it will engage a striking surface of the rocker to rock it to an engaged position in a closing direction in which the part of the rocker opposite to the striking surface overlies and retains the pin.

In one form of the present invention the rocker is mounted in the base by means of a pair of pivots or trunnions leaving its center clear so that the pin can move across the pivotal axis.

The base may afford or be provided with shields which in the closed position project up beyond the rocker on either side of it. Such shields will tend to prevent clothes or other surfaces which may rub past the catch from turning the rocker in a direction to release the catch. Preferably the shields also extend forward beyond the front edge of the rocker in the engaged position.

In one construction the part of the rocker opposite the striking surface, which may be termed its roof, affords a forward retaining surrace and a rear retaining surface both of which can engage the pin, and which are spaced apart along the length of the tube, and the surface of the roof between the said surfaces is set back from a straight line joining them. For example, one retaining surface may be afforded by the forward end portion of the roof, while the other may be afforded by a projection formed by distorting the roof inwardly towards the axis in a region diagonally opposite to the striking surface. The pressure of the pin on the rear retaining surface will tend to rock the rocker in the closing direction while the forward retaining surface will insure that the rocker must turn through a substantial angle before freeing the pin. The intervening part of the roof is preferably set back at the position where it is most likely to foul the tip of the pin as it enters the catch and turns the rocker to its closed position, thus enabling clearances to be reduced.

The invention may be employed in various ways but one specific embodiment will be described by way of example with reference to the accompanying drawings, in which:

FIGURE 1 is a side elevation of a fastening device in accordance with the invention in the engaged position;

FIGURE 2 is a similar view of the catch in the released position;

FIGURE 3 is a plan View of the catch in the released position;

3,1382% Patented Jan. 21, 1964- "ice FIGURE 4 is a perspective view of the rocker removed from the base;

FIGURE 5 is a perspective view of the base without the rocker, and

FIGURE 6 is a diagram showing the path of the tip of the pin relative to the rocker.

The fastening device is shown in FIGURE 1 as applied to an article such as a brooch 10 to which the catch 11 and a suitable bearing 12 for the pin 13 would normally be separately secured, as by soldering. The drawings show the device greatly enlarged, and in fact the total height of the catch might be of the order of A3 inch.

The bearing 12 for the pin forms no part of the invention and may be of any convenient form, providing a certain degree of resilience either in the pin itself or in the hearing, so that when the pin is pressed down into the catch it tends to spring up again.

The catch in accordance with the invention is extremely simple both in construction and use, and comprises only two parts, a base 15 shown in FIGURE 5, and a rocker 16 shown in FIGURE 4. The rocker is in the form of a flattened tube or cylinder having a pair of holes 17 punched in its opposite flattened faces. Its rear end is inclined as shown so that whereas the front edge is slightly shorter than the major diameter the rear edge is appreciably longer and provides an actuating projection 18. The forward edge is approximately square to the axis of the tube. The top wall of the rocker near its rear end, is formed with a depression or dimple 21 to contact the pin.

The base 15 comprises a strip bent up to U form to receive the rocker. Each leg of the U has a depression 19 punched in its outer face to form a corresponding projection on its inner face to enter the holes 17 in the rocker when assembled to form a pivot for the latter.

In operation, to close the fastening device it is only necessary to press the pin down into the catch. The lower part of the front edge of the rocker forms a striking surface 29 which the pin engages so as to turn the rocker about its pivot, to its closed position. As soon as the pin is released it tends to spring up again and its engagement with the top of the rocker tends to turn the latter still further in the closing direction. In this connection the depression or dimple 21 in the upper surface of the rocker near its rear end ensures that contact is made at a point further than the rocker pivot from the pin pivot, so as to accentuate the tendency to keep the catch closed.

It will be noted from FIGURE 1 that the whole of the forward and upper edges of the rocker when in the closed position are masked by the limbs of the U-shaped base which provide efiective shields to prevent the rocker from being turned to the released position by the rubbing action of cloth (shown diagrammatically at 25) the precise action which would be produced for example by attempting to withdraw the pin from the cloth. The only part of the rocker that projects beyond the shields is the extreme rear end of the upper edge which forms the actuating projection 18. The catch can be very easily and conveniently released at will by pressing down this actuating projection.

It will be realized that in order to exert a restoring couple the pin must extend beyond the rocker pivot. The use of trunnions as the pivot for the rocker enables the pin to extend beyond their axis and yet to be pressed down below this axis. This point is of some importance to the achievement of a compact construction which operates efliciently, since it will be realized that, as the pin turns the rocker, the most favorable positions are those in which the radius from the rocker pivot axis to the striking surface is in line with, or makes a small angle with, the length of the pin. At positions above and below this position the parts reach top and bottom dead centers in which the pressure of the pin exerts no turning couple on the rocker. Hence the most favorable range is above and below a position in which this radius extends towards the pin pivot. If a solid rocker pivot pin limits the extent to which the pin can be pressed down, it is more diflicult to insure that the rocker is turned easily an eliably through a sufficient angle.

FIGURE 6 is a diagram indicating some of the desiderata concerning the shapes and proportions of the parts of the catch in relation to the pin. For simplicity the thickness of the pin is neglected and the pin is assumed to remain parallel to a given direction once it has engaged the catch.

The curve 353 shows the locus of the point of the pin (indicated by an arrow head) relatively to the rocker (which is assumed to remain stationary while the base and pin swing round) from the moment the pin engages the striking point 26 in the position 31 through the position 32 in which it is in line with the rocker pivot to the fully engaged position 33. The pin is then released and springs up again to the position 34 or 35 without altering its angular relationship to the rocker.

Naturally it is desirable to rely as little as possible on the resilience of the pin and hence the distance between the positions 33 and 34 or 35 should be reduced to a minimum, so that the position 34 is preferable to the position 35.

To give the maximum security the pin should engage the roof of the rocker as close as possible to its point, namely in the region 37 since engagement with a rear retaining surface in this region gives a maximum couple tending to turn the rocker towards its engaged position due to the resilience of the pin. If the engagement were only at this point the rocker would not be in equilibrium and hence it should also engage a forward retaining surface at its forward end as at 38. In this condition the pressure will be shared between the regions 37 and 38 but the slightest tilting of the rocker in the releasing direction will shift the whole pressure to the region 37 so as to return it to the engaged position. At the same time the rocker will have to turn through a large angle before the forward retaining surface 38 will clear the end of the pin, so that the danger of inadvertent release is reduced in two ways.

The rocker could be kept in equilibrium if the pressure were confined to a single region 39 in line with the pivot 19 of the rocker, but in this case appreciable movement in a releasing direction would have to take place before an appreciable restoring couple would build up. In addition if the rocker were shaped to en age the pin at the region 39 in the position 34 it would foul the tip of the pin at a position between the positions 31 and 32 as shown by the intersection of the region 39 with the curve 3% at the position in question. It is also desirable that the rocker should extend to the region 37 to mask the end of the pin and prevent it from scratching people or things.

Hence it is desirable that the roof of the rocker should protrude to the rear and front retaining surfaces 37 and 38 but should be concave or set back in between'so as to keep clear of the curve 30.

In the practical construction described above this desideratum is approached by distorting the roof of the rocker from its initial straight profile by forming the depression 21, but it will be appreciated that a similar effect could be achieved in many other Ways, although it is desirable to insure that the surface engages the side of the pin tangentially rather than pressing against its point, so that the force is in a direction to exert the maximum restoring couple.

FIGURE 6 is of course idealized as it makes no allowance for the thickness or taper of the pin the bluntness of its point or its change of angular position even after it has engaged the catch. Moreover in practice the parts cannot be made with perfect accuracy bearing in mind that the metal is bent to radii of curvature about equal to its thickness and the pivots may be of radius greater than the thickness of the metal, so that considerable tolerances are needed on theoretical dimensions even when produced on press tools made to a high degree of accuracy. The discussion should however sufiice to indicate, first that there is an advantage in arranging for the pin to engage a rear retaining surface of the rocker as close as possible to the end of the pin in the closed position, and as far as possible beyond the rocker pivot, and secondly that it is desirable for the pin to engage the roof of the rocker at front and rear retaining surfaces spaced apart one further and the other nearer than the pivot to the pin axis, and for the surface of the roof to be set back between these points.

Thus while the present invention does not exclude an arrangement in which the tubular rocker is so short that it could be more aptly described as a ring, it is preferred to employ a rocker of which at least the roof is of appreciable length in relation to its maximum major diameter, and to distort the roof so that its inner surface is set back between two spaced retaining surfaces.

In general it will be possible to obtain an adequate turning moment with the striking surface spaced from the rocker pivot by a relatively small distance, whereas to provide secure closing in spite of some tolerance on the length of the pin it may be necessary to space the roof from the rocker pivot by a greater distance. Hence in a preferred construction the rocker pivot is nearer to the bottom than to the roof of the rocker. Similarly the rear end of the rocker should extend far enough to mask the end of the pin in the engaged position. Hence in a preferred construction the rocker pivot is nearer to the front edge than to the rear edge of the rocker.

The fact that the catch does not embody or rely on any springs is also an important advantage. Thus when the catch is being soldered to a brooch or the like any spring in it is liable to be rendered ineffective by the heat.

it will be appreciated that the invention is not limited to the details of the construction described by way of example. Thus in particular although reference has been made to a fastening of the pin type it is not necessary that the pin should be pointed or intended to pierce clothing or the like.

Thus the fastening may be intended for use with a necklace in which case the fastening is secured to one end of the necklace and the pin is intended to pass through a ring secured to the other end of the necklace.

What I claim is:

A catch for a pin which is pivotally supported on a bearing, said catch comprising a base and a rocker connected to the base for pivotal movement about an axis, said rocker being a fiatted generally cylindrical member of oblong cross-section and including a substantially parallel front side and a longer rear side, the front side being located closer to said axis, said rear side being substantially aligned with the front side at one end of the said cyl'ndrical member and including a portion extending beyond the front side at the other end of said memher, said rocker having an opening between said sides for accommodating therein said pin, said rocker including a dimple in said portion of said rear side for engaging said pin, said pin extending over the front side of the rocker in an open position of the catch for engaging the same to pivot the rocker about said axis to a position whereat the rear side of the rocker overlies the pin and the latter is accommodated in said opening and in contact with the dimple to provide a closed position for said catch, said dimple in part projecting beyond said base in said closed position to permit release of the rocker from the closed position, said pin in said closed position contacting the dimple at a location at which the pin urges the rocker pivotaily about said axis in a direction opposing release of the rocker, said catch further comprising a trunnion arrangement pivotally coupling said rocker and base so that said is enabled to pass through said axis whereby a maximum pivotal movement of the rocker is pro Vidal References Citefl in the 111: of this patent UNITED STATES PATENTS 531,458 Bryan Dec. 25, 1894 Zelly Sept. 9, 1902 Liebert Sept. 1, 1908 Thurstans Oct. 26, 1909 Goidsmith Ju1y 4, 1911 Bennett May 18, 1915 Folkman Jan. 15, 1929 

